Andrew Weil

I have argued that every human being is born with an innate drive to experience altered states of consciousness periodically - in particular to learn how to get away from ordinary ego-centered consciousness. I have also explained my intuition that this drive is a most important factor in our evolution, both as individuals and as a species. Non-ordinary experiences are vital to us because they are expressions of our unconscious minds, and the integration of conscious and unconscious experience is the key to life, health, and spiritual development, and fullest use of our nervous systems. By instilling fear and guilt about altered states of consciousness into our children, we force this drive underground, guaranteeing that it will be expressed in antisocial ways.

Andrew Weil

Source: The Natural Mind: A Revolutionary Approach to the Drug Problem

"The desire to transcend one's own ego boundaries, to share completely, even for a moment, the consciousness of another person must be a universal longing. It motivates many of our activities from taking drugs to making love, and lies behind the search for new ways of getting close to one another that is so intense in our society today."

Andrew Weil

Source: Wizard of the upper Amazon - the story of Manuel Cordova Rios - Bruce Lamb - in the intro from Andrew Weil